@uncle_bob: I don't follow. The motors are attached to the bottom. You might have to draw me a picture. (I have consided mounting the steppers on top of the build plate a few times since the height of a stepper/coupler stack is about the same length as the unused thread. However, this solution is fraught with a few engineering gotchas so I keep discarding it. If I really wanted anouther 3+ inches for free I would keep everything as it is but cut an access hole in the mid plate and move the build platform to the bottom. This doesn't make sense for a desktop solution but it might for a 1.5X+ LISA.)
@CTF: LISA's print quality is as good as I have ever gotten/saw. I would put her up against most any printer. Getting good prints out of most printers is kind of like continuous arm wrestling. Sometime you make improvements and some time you slip up. It always takes effort. :-)
@Everyone:
[attachment 23920 lisa1.jpg]
115x115x115 print
&
190x190x190 print
[attachment 23921 lisa2.jpg]
First layer
[attachment 23922 lisa3.jpg]
Bridging (71mm bridge at the top and then each one is 10mm shorter)
Lots of good news. All the distances are so well defined that LISA holds to a plane like a champ. I have done no tweaking to keep LISA from doing the tradition Rostock cupping problem. I was able to use the whole print bed with only a couple of judiciously induced skipped steps. I am very happy with all the results and would use this over my Printrbot for most things.
Some not as good news. I tried taking pictures but there are some very subtle artifacts from screw wobble and for some strange reason there is a hint of a backlash artifact from one screw. Again, I tried to take pictures of these flaws but they are beyond the ability of my camera phone to capture. Most people wouldn't notice unless I pointed it out to them and made them run their fingers over it. The artifacts are some inconsequential that I am considering leaving LISA-0 with the 3/8" screws (It prints great every time so I think it will get inserted into my student's bot farm.) and building another one with the 7/16". I want to try a few more things so maybe another build is the way to go.
I think I am going to add to very stiff bed leveling springs to make in flight layer adjustment a snap. There is no need for a leveling probe.
@CTF: LISA's print quality is as good as I have ever gotten/saw. I would put her up against most any printer. Getting good prints out of most printers is kind of like continuous arm wrestling. Sometime you make improvements and some time you slip up. It always takes effort. :-)
@Everyone:
[attachment 23920 lisa1.jpg]
115x115x115 print
&
190x190x190 print
[attachment 23921 lisa2.jpg]
First layer
[attachment 23922 lisa3.jpg]
Bridging (71mm bridge at the top and then each one is 10mm shorter)
Lots of good news. All the distances are so well defined that LISA holds to a plane like a champ. I have done no tweaking to keep LISA from doing the tradition Rostock cupping problem. I was able to use the whole print bed with only a couple of judiciously induced skipped steps. I am very happy with all the results and would use this over my Printrbot for most things.
Some not as good news. I tried taking pictures but there are some very subtle artifacts from screw wobble and for some strange reason there is a hint of a backlash artifact from one screw. Again, I tried to take pictures of these flaws but they are beyond the ability of my camera phone to capture. Most people wouldn't notice unless I pointed it out to them and made them run their fingers over it. The artifacts are some inconsequential that I am considering leaving LISA-0 with the 3/8" screws (It prints great every time so I think it will get inserted into my student's bot farm.) and building another one with the 7/16". I want to try a few more things so maybe another build is the way to go.
I think I am going to add to very stiff bed leveling springs to make in flight layer adjustment a snap. There is no need for a leveling probe.